This invention relates to textile articles with heating/warming, and more particularly to such heating/warming textile articles incorporating phase change components.
All common forms of chemical matter are found in one of three phases, i.e. solid, liquid, or gas, depending upon temperature and pressure conditions of the local environment. It is known that a change of phase requires either release of latent heat energy or requires addition of latent heat energy. More specifically, changing the phase of a material from solid to liquid or from liquid to gas (or, in the case of, e.g., carbon dioxide or xe2x80x9cdry icexe2x80x9d directly from solid to gas) requires addition (application) of a predetermined amount of energy (heat), measured, e.g., in calories. Conversely, change of phase of a material from gas to liquid or from liquid to solid (or gas to solid) requires release or removal of energy (heat). Each change of phase for a particular material, or combination of materials, occurs under predetermined combinations of temperature and pressure.
Others have suggested employing phase change materials in thermal insulation. For example, Colvin et al. U.S. Pat. No. 5,804,297 describes a coating employing microencapsulated phase change material for the purpose of insulating a substrate against thermal transients or impulses.
According to the invention, a heating/warming textile article consists of a fabric body with electrical resistance heating/warming elements that generate heating/warming upon application of electrical power, e.g., from a battery mounted to the fabric body, and the fabric body further includes a phase change component formulated to change phase in the temperature range of use of the textile article, to cyclically absorb and release latent heat, thus to conserve and extend the useful life of the battery.
According to one aspect of the invention, a heating/warming textile article includes a fabric body, an electrical resistance element attached to the fabric body, the electrical resistance element capable of being electrically coupled to and uncoupled from an electrical power source to cyclically provide electrical power to the electrical resistance element for providing heating/warming of the textile article, and a phase change component associated with the fabric body and including a phase change material formulated to change phase in a temperature range of use of the textile article, to cyclically absorb and release latent heat in a manner capable of conserving use of the electrical power source.
Variations of this aspect of the invention may include one or more of the following features. The phase change component includes a phase change fiber that microencapsulates the phase change material. The phase change fiber at least partially forms the fabric body. The phase change fiber is incorporated into the fabric body. The phase change fiber is attached to the fabric body by at least one of knitting, weaving, stitching, embroidery stitching, laminating and applying an adhesive. The phase change component includes a coating of phase change material on fibers the fabric body. The electrical resistance element includes a conductive yarn and the phase change component comprises a coating on the conductive yarn. The electrical resistance element includes a conductive yarn and the phase change fiber is stranded together with the conductive yarn. The temperature range of use of the textile article is about 32xc2x0 F. to about 120xc2x0 F. The phase change material includes at least one of paraffin and glycol. The power supply is a battery. The battery is mounted to the article. The heating/warming textile article includes a controller for controlling the electrical power supplied from the power supply to the electrical resistance elements. The controller includes a timer. The controller includes a thermostat.
In another aspect, the invention provides a method of conserving a useful life of a battery used to power a heating/warming textile article, the article including electrical resistance elements. The method includes associating a phase change component with the fabric body, the phase change component including a phase change material formulated to change phase in a temperature range of use of the textile article; applying power from the battery to the electrical resistance elements to raise the temperature of the heating/warming article and to cause the phase change material to change from a first phase to a second phase; electrically disconnecting the battery from the electrical resistance elements; and allowing the phase change material to change phase from the second phase to the first phase before applying additional power from the battery to the resistance elements.
According to another aspect of the invention, a heating/warming textile article consists of a fabric body with electrical resistance heating/warming elements that generate heating/warming upon application of electrical power, e.g., from a battery mounted to the fabric body, and the fabric body further includes a phase change component formulated to change phase in the temperature range of use of the textile article, to cyclically absorb and release latent heat, thus to conserve and extend the useful life of the battery.
The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings.